1. Field of the Invention
This invention relates to polishing II-VI compound semiconductor single crystals to a mirror flat and stress-free condition.
2. Prior Art
For polishing thin films, it is conventional to use a bromine base solution as the polishing agent (e.g.) bromine methanol, bromine lactic acid or bromine ethylene glycol. However, bromine is very volatile and its fumes readily react with metals. It is really a pollutant which is hazardous to creatures. Another great disadvantage of bromine is the fact that control of the concentration of solution is not simple due to its volatility.
Control of smoothness in polishing single crystals is most critical, followed by control of flatness, and both depend upon being able to calculate the rate of material removal so overshoot is not encountered. The volatility of bromine renders this difficult if not impossible which is fatal when polishing thin films.